Abstract
Traditional industrial hygiene assessment of exposure to polychlorinated biphenyls (PCBs) has long focused on air concentrations as a surrogate measure of worker dose. Evidence is presented to support the hypothesis that the dermal and dermal/oral routes of worker PCB exposure are major contributors to total PCB body burden in the group of transformer maintenance and repair personnel studied. Additional evidence is presented to demonstrate the critical role of work practices in determining PCB exposure. These hypotheses challenge the long-held notion of the pre-eminent importance of respiratory exposure to PCBs.